Folding Wing Root Mechanism

ABSTRACT

Improvements to the hinge of a folding aircraft wing including a load bearing hinge mechanism with multiple locking mechanisms. The mechanism includes rigid panels that cover the hinge area when the wing is deployed, and the wing itself covers the hinge area when the wing is retracted. A control lever is used to actuate the wing and incorporates safety features to prevent unwanted actuation.

FEDERALLY SPONSORED RESEARCH

Not Applicable

SEQUENCE LISTING OR PROGRAM

Not Applicable

FIELD OF THE INVENTION

This invention relates to aircraft and to roadable aircraft, a type ofaircraft that can be converted into an automotive type vehicle capableof driving on the road, sometimes popularly referred to as a “flyingcar” or “flying-driving vehicle”.

BACKGROUND OF THE INVENTION

This invention, though extensible to a broader spectrum of applications,was motivated by the development of a roadable aircraft. One of thechallenges of developing a practical roadable aircraft is how to safelyand securely stow the wings while operating in the road environment.Conveniently stowing a roadable or non-roadable aircraft's wings forstorage could be accomplished with the same or similar techniques. Thisinvention represents an improved method for accomplishing this.

A common method for stowing the wings of a roadable aircraft describedin prior art is to rotate the wings into an orientation parallel to thefuselage of the aircraft. This is the approach taken in broad terms byGeisse (U.S. Pat. No. 2,424,068), Spitzer (U.S. Pat. No. 6,082,665),Pellarini (U.S. Pat. No. 2,674,422), Pham (U.S. Pat. No. 5,984,228), andBragg (U.S. Pat. No. 6,086,014), among others. Some of the prior artdoes combine a fold with this rotation. The bi-fold invention describedhere improves upon this technique by reducing the side area of thevehicle on the road, thus improving safety in high-wind conditions; andby protecting more of the flight surface against potential damage fromroad debris. Additionally, a bi-folding wing can have a greater spanwhile still allowing the roadable configuration of the aircraft to fitin a standard automotive parking space.

The bi-fold invention described here has many of the same advantagesover the single fold wing designs common in naval military aircraft,such as the invention of Naumann (U.S. Pat. No. 2,712,421). A priorbi-fold wing design has been proposed by Schertz (U.S. Pat. No.3,371,886) in which the wing hinges at the top of the airfoil at boththe root and at the mid-span. The invention described here improves uponSchertz in part by folding from the bottom of the airfoil. This resultsin a more compact design which requires less volume to actuate and thatoffers superior protection to the hinge in the root of the wing as it isnot exposed to the ground.

Other prior methods include wings that combine rotation and foldingmechanisms. An example of this style is seen in the concept put forth byBragg (U.S. Pat. No. 6,086,014). The complicated nature of this combinedstyle necessitates either manual operation or a heavier and morecomplicated actuation system than is put forth in this invention. Manualoperation of the wing folding and unfolding process has proven to becommercially undesirable.

The invention described here improves upon many of the detailed elementsof the prior art as well as the basic configuration of the stowed wings.For optimum aerodynamic performance and protection of key mechanisms inboth the stowed and deployed configuration, this invention improves uponthe fairing panels described by Paez (U.S. Pat. No. 5,372,336) byproviding a fair surface in both configurations. Also, instead of addingan additional third rigid component to fair the wing surface only in thedeployed configuration, this invention simplifies the fairing by usingtwo panels connected to the fuselage and inboard wing section. The panelfairing technique presented here is an improvement for roadableapplications over the elastomeric fairing proposed by Gruensfelder (U.S.Pat. No. 6,076,766) as it provides a more durable and cost-effectivemethod of fairing the surface of the structure.

Any safe folding wing mechanism must also include a method by which thewings are secured in place in both its folded and deployedconfigurations. In the prior art, this is often accomplished through theuse of locking pins. This method is seen in both military and roadableaircraft folding wing mechanisms. See Veile (U.S. Pat. No. 5,558,229)and Spitzer (U.S. Pat. No. 6,082,665) for an example of each. Theinvention described here is an improvement on previous wing lockingtechniques as it allows a quick, simple, direct visible and tactilecheck of the locking mechanism before flight by the pilot to ensure safeoperation.

The locking and unlocking mechanisms are activated by the same automatedprocess as the wing folding and deployment, thus eliminating the needfor secondary mechanisms. This is an improvement over inventions such asthat described by Pham (U.S. Pat. No. 6,129,306) in which a pin isinserted for flight and a bungee cord is required to secure the wingswhen stowed. By eliminating sliding components in the wing root, thepotential for debris to interfere with the folding and locking operationis significantly reduced. The wing locks described in this invention arean improvement over prior art in that they are both safer and moreconvenient than previous roadable aircraft locking mechanisms whilebeing simpler and lighter weight than military wing locking devices.

In broad terms, when used in the preferred embodiment, the inventionpresented here represents part of a more elegant and more commerciallyviable solution to the challenge of folding the wings on a roadableaircraft for ground use than those previously conceived.

SUMMARY OF THE INVENTION

The invention covers improvements to the root-wing hinge area of abi-fold aircraft wing including a load bearing hinge mechanism withmultiple locking mechanisms. While the preferred embodiment is the useof these mechanisms at the root fold in a bi-fold wing for a roadableaircraft, aspects of this invention can be applied to single-fold andnon-roadable applications.

The inner wing section is hinged to the vehicle along the bottom skin ofthe wing. Hinging at the bottom has advantages compared to hinging alongthe top of the wing. For example: the span of the wing can be longer fora given stowed wing size, and the folding mechanism can be made easilyprotected from the elements. The loads from the wing spar aretransmitted to the body of the vehicle through the hinge on the bottomof the wing, and a retractable linkage on the top skin of the wing. Asingle linear actuator acting on the linkage can retract or deploy thewing, and in the deployed position, the linkage moves to anover-top-dead-center position, so wing load forces hold the linkage inthe deployed position. Also there is a secondary locking mechanismpreventing the linkage from folding, and the actuator isnon-backdrivable. These three mechanisms provide a high level ofconfidence that the wing will not accidentally retract during flightactivities. Another improvement embodied in this linkage is the abilityof the pilot to perform both a direct visual and direct tactile check onits being in the locked position during the course of a standardpre-flight inspection of the aircraft. Furthermore, the wing has rigidpanels that cover the hinge area when the wing is deployed, and the wingitself covers the hinge area when the wing is retracted. This is animprovement on other mechanisms because the vehicle is left with cleanlines and a sealed hinge mechanism in both the retracted and deployedpositions. Frequently folding wings leave exposed mechanism and opengaps in the retracted position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross sectional side view of the hinge mechanism.

FIG. 2 is a schematic of the exterior of the root of the wing with thefairing panels in place.

NUMBERED COMPONENTS IN THE DRAWINGS

-   5. Hinge Link No. 1-   6. Hinge Link No. 2-   7. Hinge Link No. 3-   8. Hinge Link No. 4-   9. Lower Hinge Base-   10. Lower Hinge Wing Side-   11. Lower Hinge Pin-   12. Upper Hinge Pin No. 1-   13. Upper Hinge Pin No. 2-   14. Upper Hinge Pin No. 3-   24. Aircraft Body-   25. Front Cover Panel-   26. Mid Cover Panel-   27. Rear Cover Panel-   28. Spar Web-   30. Over-Center Lock-   31. Stop-   32. Actuator Pivot-   33. Actuator-   34. Spring-   35. Cable-   36. Pivot-   50. Inner Wing

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows the wing folding mechanism. In the preferred embodimentinner wing (50) is attached rigidly to hinge link no. 4 (8) and lowerhinge wing side (10). Aircraft body (24) from which said wing will foldis mounted rigidly to hinge link no. 1 (5) and lower hinge base (9).Lower hinge base (9) and lower hinge wing side (10) are connected withlower hinge pin (11) so that the wing, attached to lower hinge wing side(10) can rotate about the axis created by lower hinge pin (11). The tophalf of the hinge mechanism consists of hinge link no. 1 (5) which isrigidly attached to the vehicle. Hinge link no. 2 (6) is allowed torotate with respect to hinge link no 1 (5) using upper hinge pin no. 1(12). The opposite end of hinge link no. 2 (6) is attached to hinge linkno. 3 (7) with another hinge pin, upper hinge pin no. 2 (13). Hinge linkno. 3 (7) is allowed to rotate with respect to upper hinge pin no. 2(13), and is connected to hinge link no. 4 (8) with another hinge pin,upper hinge pin no. 3 (14). Hinge link no. 4 (8) is rigidly connected tolower hinge wing side (10) with spar web (28); all three move with innerwing (50). Actuator pivot (32) is a rigid extension of hinge link no. 2(6), and actuator pivot (32) has a pivoting connection to actuator (33).Over-center lock (30) can rotate about pivot (36), and stop (31) is afixed stop rigidly attached to hinge link no. 2 (6).

The operation of the wing folding mechanism is as follows: To extend thewing from a retracted position the actuator (33) pulls on the actuatorpivot (32), which moves to the left causing hinge link no. 2 (6) torotate in a counterclockwise manner about upper hinge pin 2 (12). Sincehinge link no. 4 (8) and lower hinge wing side (10) are rigidly linkedthrough spar web (28), as hinge link no. 2 (6) pushes upper hinge pinno. 2 (13) towards the right, upper hinge pin no. 3 (14) traces acircular path clockwise about lower hinge pin (11). The resultingrotation of hinge link no. 4 (8) and lower hinge wing side (10) rotatesinner wing (50) clockwise from the retracted position to the extendedposition.

Once inner wing (50) is extended, hinge link no. 2 (6) has rotated to aposition over top-dead-center, so positive wing lift forces which aretransmitted as compressive forces through hinge link no. 4 (8) and thenhinge link no. 3 (7) into hinge link no. 2 (6) tend to push (6) upwards.Since hinge link no. 2 (6), specifically the end of (6) containing upperhinge pin no. 2 (13) is in contact with hinge link no. 1 (5), (6) is notable to rotate counter clockwise further and the wing is prevented fromfolding back into the retracted position as a result of positive winglifting forces. Actuator (33) is non-back drivable, and will resist thismotion. In the event of negative wing lifting forces, for example thosethat might be generated during turbulence or acrobatic maneuvers, hingelink no.4 (8) and hinge link no. 3 (7) will be in tension. Hinge linkno. 2 (6) will have a force causing it to rotate fromover-top-dead-center, towards top-dead-center.

Additionally, actuator (33) is non-back drivable, and will resist thismotion. Also, over-center lock (30) is pushed to a vertical position byspring (34) and retained in position by stop (31), which also preventsexcessive clockwise motion of hinge link no. 2 (6). Once positive winglifting forces have returned, hinge link no. 2 (6) will return toover-top-dead-center. In both positive and negative wing loadingconditions, there are at least two independent mechanisms that preventthe wing from rotating into the retracted condition accidentally.

To retract the wing, a cable (35) is used to rotate over-center lock(30) out of its locked position in contact with stop (31). The actuator(33) then pushes actuator pivot (32) to the right, causing hinge linkno. 2 (6) to rotate clockwise about upper hinge pin (12). Upper hingepin no. 3 (13) pulls hinge link no. 3 (7) which pulls upper hinge pinno.3 (14) which causes hinge link no. 4 (8) to rotate counterclockwiseabout lower hinge pin (11) which rotates the wing counterclockwise intothe retracted position. Once hinge link no. (6) starts its rotation,stop (31) pushes over-center lock (30) farther out of the way causing itto continue to rotate counterclockwise about pivot (36). Over-centerlock (30) remains biased towards the locked position with spring (34).

FIG. 2 shows the panels that cover the wing folding mechanism. Frontcover panel (25) and rear cover panel (27) are rigidly affixed to innerwing (50). Mid cover panel (26) is rigidly affixed to hinge link no. 3(7). Both hinge link no. 3 (7) and hinge link no. 4 (8) are links in thehinge mechanism connecting inner wing (50) to aircraft body (24) andshown in FIG. 1.

In FIG. 2, when inner wing (50) is in the extended position in relationto aircraft body (24), front cover panel (25) and rear cover panel (27)create a flush seal to aircraft body (24) and serve to cover the areawith the wing folding mechanism, and the area cut out of aircraft body(24) where inner wing (50) will nest when it is in the folded position.During the folding process, mid cover panel (26) dives down first, ashinge link no. 3 (7) moves downwards. (The motion of hinge link no. 3(7) is fully described in FIG. 1.) As inner wing (50) rotatescounterclockwise, front cover panel (25) and rear cover panel (27) alsorotate counterclockwise, revealing a cutout in aircraft body (24) thatis the same shape as the top surface of inner wing (50). When inner wing(50) is fully retracted, the top surface rests up against the exposededge of aircraft body (24), again sealing the gap between inner wing(50) and aircraft body (24), and protecting the hinge mechanism. In thismanner the hinge mechanism is protected and sealed with a hard coveringin both the retracted and deployed positions.

1) A wing folding mechanism comprising: a) a first wing section, b) avehicle or second wing section, c) a hinge connecting said first wingsection to said vehicle, d) a first linkage located on said first wingsection with a pivot axis that is substantially parallel to but notcollinear with the pivot axis of said hinge, e) a second linkage beingjoined to said first linkage, f) a third linkage being joined to saidsecond linkage, g) a fourth linkage located on said body and connectedto said third linkage. 2) The mechanism in claim #1 wherein saidmechanism includes means for rotating said third linkage about apivoting connection to said fourth linkage whereby said first wingsection will be rotated by said means. 3) The mechanism in claim #2wherein said means is a rotary actuator, a linear actuator, manualactuator, or any other type of motion producing device. 4) The mechanismin claim #1 wherein said second and said third linkages are moved in anupward direction causing said wing to fold. 5) The mechanism in claim #1wherein said second and said third linkages are moved in a downwarddirection causing said wing to fold. 6) The mechanism in claim #1wherein a mechanical stop restricts the motion of said second linkage,said third linkage, or combination thereof past a predeterminedposition. 7) The mechanism in claim #6 wherein said mechanical stop isan integrated component of either said first linkage or said fourthlinkage. 8) The mechanism in claim #1 wherein said mechanism includesmeans to rigidly locate said first linkage with respect to a componentof said hinge that is connected to said first wing section, whereby saidfirst linkage is easily aligned with said component of said hinge. 9)The mechanism in claim #8 wherein said means is a panel, integratedcomponent of said first linkage, integrated component of said componentof said hinge, or any other structure that rigidly locates said firstlinkage with said component of said hinge. 10) The mechanism in claim #1wherein said mechanism includes means to rigidly locate said fourthlinkage with respect to a component of said hinge that is connected tosaid vehicle, whereby said fourth linkage is easily aligned with saidcomponent of said hinge. 11) The mechanism in claim #10) wherein saidmeans is a panel, integrated component of said fourth linkage,integrated component of said component of said hinge, or any otherstructure that rigidly locates said fourth linkage with said componentof said hinge. 12) The mechanism in claim #1 wherein said mechanismincludes means for preventing the motion of said third linkage wherebythe wing is prevented from rotating. 13) The mechanism in claim #1wherein said mechanism includes means for preventing the motion of saidsecond linkage whereby the wing is prevented from rotating. 14) Awing-fold mechanism comprising: a) a first wing section or body section,b) a second wing or body section, c) a hinge connecting said firstsection to said second section, d) wherein said first section folds froma first position to a second position, e) where said second positionlocates said first section partly inside said second section, f) acutout in said second section so that said first section is able to foldinto said second section without interference, g) a component attachedto said first section that sufficiently covers said cutout in saidsecond section when said first section is located in the first position,whereby the maximum gap between said first section and said secondsection in both the first and second positions is substantially smallerthan the projection of the first section into said second section in thesecond position. 15) The mechanism in claim #14) wherein said firstsection is a wing section and said second section is a vehicle,aircraft, another wing panel or any object that is connected to wings.16) The mechanism in claim #14) wherein said second section is a wingsection and said first section is a vehicle, aircraft, another wingpanel or any object that is connected to wings. 17) The mechanism inclaim #14) wherein said second section is shaped to allow for theexistence of said rigid component inside of said second section withoutinterference of said second section when said first section is locatedin the second position. 18) The mechanism in claim #14) wherein saidmechanism contains a means for moving said first section from said firstposition to said second position. 19) The mechanism in claim #18)wherein a portion of said component is removed from said first sectionand attached to said means whereby said portion moves with said means,and whereby said portion becomes substantially flush-mounted with saidrigid component in said first position. 20) The mechanism in claim #19)wherein: a) said means is a wing-fold mechanism such as in claim #1 orsimilar wing fold mechanism, b) said portion is attached directly to thesecond linkage of claim #1. 21) A wing-fold control mechanismcomprising: a) a control lever in the cockpit, b) a first means forrestricting movement of said control lever, c) a second means forreleasing wing-fold locks based on the position of said lever d) a wingor a plurality of wings 22) The mechanism in claim #21) wherein saidcontrol lever has three positions. 23) The mechanism in claim #22)wherein said three positions are: a) a first position corresponding tosaid wings being unfolded, b) a second position corresponding to saidwings being unlocked, c) a third position corresponding to said wingsbeing folded. 24) The mechanism in claim #22) wherein said threepositions are: a) a first position corresponding to said wings beingunfolded, i) wherein said first means prevents said lever from enteringsaid first position unless said wings are unfolded, ii) and said firstmeans prevents said lever from leaving said first position unless a setof predetermined criteria are met, b) a second position corresponding tothe release of said wing-fold locks, c) a third position correspondingto said wings being folded, i) wherein said first means prevents saidlever from entering said third position unless said wings are folded,ii) and said first means prevents said lever from leaving said thirdposition unless a set of predetermined criteria are met. 25) Themechanism in claim #21) wherein said control lever has two positions.26) The mechanism in claim #25) wherein said two positions are: a) afirst position corresponding to said wings being locked in either afolded or an unfolded position, i) wherein said first means preventssaid lever from entering said first position unless said wings areunfolded or folded, ii) and said first means prevents said lever fromleaving said first position unless a set of predetermined criteria aremet, b) a second position corresponding to said wings being unlocked.27) The mechanism in claim #25) wherein said two positions are: a) afirst position corresponding to said wings being in a folded positionwherein said first means prevents said lever from changing from saidfirst position to said second position unless a set of predeterminedcriteria are met, b) a second position corresponding to said wings beingin a unfolded position wherein said first means prevents said lever fromchanging from said second position to said first position unless a setof predetermined criteria are met. 28) The mechanism in claim #21)wherein said first means is a number of solenoids, mechanical locks,electromechanical locks, or any other method of restricting the motionof said control lever. 29) The mechanism in claim #21) wherein saidfirst means are controlled by a security means for identify andvalidating the operator of said wing-fold mechanism 30) The mechanism inclaim #29) wherein said security means is comprised of a pin-pad device,or a biometric identification device, a key lock, combination lock, orany other means of preventing unauthorized access. 31) The mechanism inclaim #21) wherein said second means is comprised of a number of controlcables connected to said control lever on one side of said controlcables, and connected to said wing-fold locks on the other side of saidcontrol cables. 32) The mechanism in claim #21) wherein said secondmeans is comprised of a number of sensors that determine the position ofsaid control lever and remotely releases and activates said wing-foldlocks.